杏吧原创

THERE鈥橲 an old joke about the theoretical physicist who claims to have worked out the reason for a sudden drop in milk production at the local dairy farm. The biologist, ecologist and nutritionist all failed to solve the problem, and are curious to hear how it was done. 鈥淲ell,鈥� says the physicist, 鈥渃onsider a spherical cow鈥︹��. The joke is that physicists reduce problems to a simple form to ease their calculations, even if that makes their model irrelevant to the real world.

has the last laugh. In Living at Micro Scale, he begins with the assumption that micro-organisms can be considered as spherical bodies, and then goes on to show how simplifications of that kind can demonstrate how deeply the physics of fluids has influenced the behaviour and evolution of microbes.

For example, from the buffeting the tiniest of cells receive from the molecules around them, Dusenbery predicts they should not be capable of powered swimming 鈥� and they aren鈥檛. At a slightly larger scale, water behaves as a highly viscous fluid, and from this physics suggests that microbes should swim through it using rod-shaped, not paddle-shaped appendages 鈥� and they do.

The book draws on 20 years of Dusenbery鈥檚 own research, and he doesn鈥檛 compromise on the science; informed readers will find all the equations they could need. But it is rarely dry or uninteresting, and benefits from a liberal scattering of anecdotes going back 2500 years. My favourite is the idea that Galileo fell foul of the church because of his atomist view of matter.

Anecdotes also abound in Nanoscale. While Dusenbery builds on one central idea, the Deffeyes鈥檚 book is a celebration of the entire microscopic world, with an emphasis on crystallography, giving us insights into science we cannot 鈥渟ee鈥�. It is divided into 50 themed essays, with beautiful illustrations such as the end-on view of a fibrous virus (right). The essays, which tend to focus on the history of discovery, have a personal and lively feel. So we see how the 18th-century mineralogist smashed his impressive collection of calcite crystals to show that minerals were constructed from universal building blocks that would always break into similar shapes.

Other essays address modern nanotechnology. Carbon nanotubes inevitably get a mention, and the book explores supercapacitors, superconductors and even memristors, the resistors-with-a-memory built for the first time only last year. Some of this is so new that the behaviour of these materials is, at times, still not fully understood.